Background: Psychiatric patients have been well documented to have higher rates of physical illness compared to the general population. Treatments of chronic illnesses such as functional gastrointestinal disorders are beginning to incorporate integrated care models to simultaneously address psychiatric and physical symptoms. This is based on recent research emphasizing the importance of the gut-brain axis. However, the intricacies of connections between infectious diseases and mental illness remain unclear. Diarrheal disease and depression account for a disproportionate amount of the total global burden of disease, being the second and fourth greatest contributors respectively. This highlights the need to investigate the possible links between the two, and interactions along the gut-brain axis in general. Objectives: The objectives of this scoping review and thematic analysis was to explore what is known about infectious acute gastrointestinal illness and its relationship to depressive and anxiety symptoms. Ultimately, this review was intended to act as a case study of novel connections between infectious illnesses and mental illness. Methodology: Following Arksey & O’Malley’s framework, five databases (EMBASE, MedLine, PsychInfo, Global Health, HealthStar) were searched resulting in 1156 titles and abstracts. These were screened for inclusion and produced a total of 17 articles included for review and synthesis. Results: Three major themes were identified: 1) Connections between physical and mental status within this context can occur via i) the microbiome, ii) the immune system, iii) the nervous system, and iv) the endocrine system; 2) Bidirectionality of the gut-brain axis is key in understanding cross-talk between symptoms; 3) Integration of care options might result in improved health outcomes. Conclusion: These findings demonstrate that holistic and integrated interventions must be considered not only for chronic and mental illnesses, but also for infectious and mental illnesses, based on the connections between AGI and depressive and anxiety symptoms. More research is required, particularly with human subjects, in order to further understand the connections between the gut and brain. Incorporation of this knowledge into new treatment plans will allow clinicians to deliver more effective care to their patients who suffer from a dual burden of disease. / Thesis / Master of Science (MSc)

Current and potential future trends in the burden of acute gastrointestinal illness (AGI) in Rigolet, Nunatsiavut and Iqaluit, Nunavut, Canada were investigated in the context of climate change. A concurrent mixed methods design was used in which quantitative and qualitative data were concurrently collected and analyzed and then combined to better understand the burden of AGI. In-depth interviews with government stakeholders (n=11), PhotoVoice workshops (n=11), and two community surveys (n=185) were conducted to identify and characterize climate-sensitive health priorities in the Nunatsiavut region. Then, four cross-sectional retrospective surveys in Rigolet (two community censuses, n=462) and Iqaluit (two surveys with randomly selected households, n=1,055), as well as in-depth interviews with cases (n=9) were conducted to examine the incidence, risk factors, and healthcare seeking behavior of AGI. Finally, a scenario planning approach was used to identify and rank trends and conditions driving changes in future waterborne disease in Nunatsiavut. This involved in-depth interviews with national and international experts (n=20) and community focus group discussions (n=29). Climate-sensitive health priorities identified in Nunatsiavut included food security, water security, mental health, new hazards and safety concerns, and health services and delivery. The annual estimated incidence of self-reported AGI ranged from 2.9-3.9 cases/person/year in Rigolet and Iqaluit, which are the highest published estimates globally. Significant risk factors for AGI included food, water, animal exposure, and socio-economic conditions; while community interviewees perceived hygiene, retail food, tap water, boil water advisories, and personal stress to be important risk factors. The proportion of AGI cases seeking medical services ranged from 3-19%, which are among the lowest published rates globally. In the scenario planning process, critical drivers of AGI included ‘extreme weather events’; ‘technology development’; and ‘global interest in Northern resources’. These results provided information about AGI-related exposures and sensitivities to climate change, which can be used to provide information for public health planning, prioritization, and programming in Inuit regions. The improved understanding of AGI in two Canadian Aboriginal communities sheds light on the need to better understand the burden in sub-sets of the population that might be at higher risk, including Aboriginal populations in the context of climate change. / Vanier Canada Graduate Scholarship (CIHR); Public Health Agency of Canada; IRIACC initiative (CIHR, NSERC, SSHRC, IDRC); Nasivvik Centre for Inuit Health and Changing Environments

Les épidémies de gastro-entérite aigüe liées à l’eau du robinet demeurent un enjeu de santé publique au 21ème siècle dans les pays développés. La majorité des dispositifs de surveillance mis en place dans les pays se caractérisent par une sous-déclaration. En France, l’amélioration de la surveillance de ces évènements repose sur l’exploitation des données de l’Assurance Maladie. L’objectif de notre travail est de proposer une méthode pour améliorer la sensibilité et la spécificité de la détection des épidémies de gastro-entérite aigüe d’origine hydrique. Trois études ont été menées pour i) évaluer la capacité des données de l’Assurance Maladie à décrire des épidémies de gastro-entérite aigüe d’origine hydrique, ii) adapter une méthode de détection spatio-temporelle en intégrant l’exposition à l’eau du robinet, iii) évaluer les performances de cette méthode. Notre travail a permis de développer une méthode de détection spatio-temporelle des épidémies hydriques en tenant compte des unités géographiques de distribution d’eau avec une bonne sensibilité et une bonne valeur prédictive positive. Les performances de détection sont principalement liées à la taille de l’épidémie. La capacité des données de l’Assurance Maladie à détecter des épidémies d’origine hydrique peut être influencée par les habitudes de recours aux soins, la sensibilisation de la population au risque infectieux d’origine hydrique et le niveau d’agrégation temporel des cas de gastro-entérite aigüe. La finalité de nos travaux de recherche est l’application opérationnelle pour la détection automatisée des épidémies hydriques dans une finalité de prévention et de réduction de leur impact sanitaire. / Waterborne disease outbreaks (WBDO) of acute gastrointestinal illness remain a public health concern in the 21st century in developed countries. Almost all surveillance systems implemented in countries are characterized by underreporting. In France, the improvement of monitoring these events is based on the use of data from the French Health Insurance. The aim of our work was to propose a method to improve the sensitivity and specificity of the detection of WBDO. Three studies were conducted to i) evaluate the ability of French Health Insurance data to describe WBDO ii) apply a method of space-time detection by integrating the exposure to tap water, iii) evaluate the performance of this method. Our work allowed developing a method of space-time detection of WBDO by taking into account geographical units for drinking water networks units with a good sensitivity and positive predictive value. The performances for detection are mainly related to the size of the epidemic. The ability of the data from the French Health Insurance to detect WBDO can be influenced by the health-seeking behavior of people, awareness of the population to the risk of WBDO and the temporal aggregation level of cases of acute gastrointestinal illness. The purpose of our research is to carry out an operational design for the automated detection of WBDO in a purpose of prevention and reduction of health impact.